K. Nakajima, T. Batpurev, W. M. Chan, F. Dokaku, K. Fushimi, K. Kanagawa, S. Katagiri, K. Kawasaki, B. T. Khai, H. Kino, E. Kinoshita, T. Kishimoto, R. Hazama, H. Hiraoka, Daiki Hiyama, T. Iida, M. Ishikawa, Xiaolong Li, T. Maeda, K. Matsuoka, M. Moser, M. Nomachi, I. Ogawa, T. Ohata, Hiroyoshi Sato, K. Shamoto, M. Shimada, M. Shokati, N. Takahashi, Y. Takemoto, Y. Takihira, Y. Tamagawa, M. Tozawa, K. Teranishi, K. Tetsuno, V. Trang, M. Tsuzuki, S. Umehara, Wei Wang, S. Yoshida, N. Yotsunaga
In the CANDLES experiment aiming to search for the very rare neutrino-less double beta decays (0νββ) using 48Ca, we introduced a new shielding system for high energy γ-rays from neutron captures in massive materials near the detector, in addition to the background reduction for 232Th decays in the 0νββ target of CaF2 crystals. The method of background reduction and the performance of newly installed shielding system are described.
{"title":"Upgrading of shielding for rare decay search in CANDLES","authors":"K. Nakajima, T. Batpurev, W. M. Chan, F. Dokaku, K. Fushimi, K. Kanagawa, S. Katagiri, K. Kawasaki, B. T. Khai, H. Kino, E. Kinoshita, T. Kishimoto, R. Hazama, H. Hiraoka, Daiki Hiyama, T. Iida, M. Ishikawa, Xiaolong Li, T. Maeda, K. Matsuoka, M. Moser, M. Nomachi, I. Ogawa, T. Ohata, Hiroyoshi Sato, K. Shamoto, M. Shimada, M. Shokati, N. Takahashi, Y. Takemoto, Y. Takihira, Y. Tamagawa, M. Tozawa, K. Teranishi, K. Tetsuno, V. Trang, M. Tsuzuki, S. Umehara, Wei Wang, S. Yoshida, N. Yotsunaga","doi":"10.15669/PNST.6.144","DOIUrl":"https://doi.org/10.15669/PNST.6.144","url":null,"abstract":"In the CANDLES experiment aiming to search for the very rare neutrino-less double beta decays (0νββ) using 48Ca, we introduced a new shielding system for high energy γ-rays from neutron captures in massive materials near the detector, in addition to the background reduction for 232Th decays in the 0νββ target of CaF2 crystals. The method of background reduction and the performance of newly installed shielding system are described.","PeriodicalId":20706,"journal":{"name":"Progress in Nuclear Science and Technology","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82516593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kenichi Watanabe, Tomoaki Mizukoshi, A. Yamazaki, S. Yoshihashi, A. Uritani, T. Iguchi, Tomohiro Ogata, T. Muramatsu, Tetsuro Matsumoto, A. Masuda
{"title":"Response evaluation of Onion-like single Bonner sphere neutron spectrometer using TRUST Eu:LiCAF scintillator","authors":"Kenichi Watanabe, Tomoaki Mizukoshi, A. Yamazaki, S. Yoshihashi, A. Uritani, T. Iguchi, Tomohiro Ogata, T. Muramatsu, Tetsuro Matsumoto, A. Masuda","doi":"10.15669/PNST.6.122","DOIUrl":"https://doi.org/10.15669/PNST.6.122","url":null,"abstract":"","PeriodicalId":20706,"journal":{"name":"Progress in Nuclear Science and Technology","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78973385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tokyo Electric Power Company has been planning that a part of rubbles arising from the accident of the Fukushima Daiichi NPS (1F) will be recycled and applied in a restricted reuse only within 1F site. For ensuring the safety of the restricted reuse, we have been developing a new methodology for evaluation of reference concentration for the restricted reuse, considering current situation of radiation control at the 1F site. In this study, in order to validate the reference radiocesium concentrations of recycling material used for the road (1.0×105 Bq/kg) and the base of a concrete building (1.6×105 Bq/kg), which have been calculated for the restricted reuse of contaminated rubbles, we evaluated (1) additional occupational dose, (2) annual dose at the site boundary, (3) radiocesium concentration in groundwater at the outlet to the ocean. (1), (2) and (3) are should be below 2 mSv/y, 1 mSv/y and 1 Bq/L, respectively. As a result, additional occupational dose was calculated as 1.3 mSv/y. Annual dose at the boundary was 1 mSv/y with condition of more than the distance of 25 m from the road. Calculated radiocesium of 134Cs and 137Cs concentrations in the groundwater at the outlet to the ocean were the below the 1 Bq/L with condition of distance of more than 5 m from the building. The calculated reference radiocesium concentrations were validated for the restricted reuse within the 1F site.
{"title":"Study on restricted use of contaminated rubble on Fukushima Daiichi NPS site (2) Validation of reference radiocesium concentration for recycling materials","authors":"Kazuji Miwa, T. Shimada, S. Takeda","doi":"10.15669/PNST.6.166","DOIUrl":"https://doi.org/10.15669/PNST.6.166","url":null,"abstract":"Tokyo Electric Power Company has been planning that a part of rubbles arising from the accident of the Fukushima Daiichi NPS (1F) will be recycled and applied in a restricted reuse only within 1F site. For ensuring the safety of the restricted reuse, we have been developing a new methodology for evaluation of reference concentration for the restricted reuse, considering current situation of radiation control at the 1F site. In this study, in order to validate the reference radiocesium concentrations of recycling material used for the road (1.0×105 Bq/kg) and the base of a concrete building (1.6×105 Bq/kg), which have been calculated for the restricted reuse of contaminated rubbles, we evaluated (1) additional occupational dose, (2) annual dose at the site boundary, (3) radiocesium concentration in groundwater at the outlet to the ocean. (1), (2) and (3) are should be below 2 mSv/y, 1 mSv/y and 1 Bq/L, respectively. As a result, additional occupational dose was calculated as 1.3 mSv/y. Annual dose at the boundary was 1 mSv/y with condition of more than the distance of 25 m from the road. Calculated radiocesium of 134Cs and 137Cs concentrations in the groundwater at the outlet to the ocean were the below the 1 Bq/L with condition of distance of more than 5 m from the building. The calculated reference radiocesium concentrations were validated for the restricted reuse within the 1F site.","PeriodicalId":20706,"journal":{"name":"Progress in Nuclear Science and Technology","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76859043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Kowatari, H. Yoshitomi, Tetsuya Ohishi, M. Yoshizawa
This work presents a framework of decision-making for additional monitoring of eye lens dose for radiation workers in reflect to the reduction of the annual dose limit of the eye lens dose. For a quantitative scheme to systematically estimate (non-) homogeneity of exposure, the proposed “homogeneity index (HI)” is introduced. The HIs were estimated by Monte Carlo calculations and found not to exceed up to 10 for γ-ray exposure situations. Applying the HI as a criterion of condition branching to decision-making process of additional monitoring of eye lens dose, proposed decision-making process was shown to cover entirely radiation workers required additional monitoring in the benchmark.
{"title":"Proposal of framework for decision making of additional monitoring of eye lens dose for radiation workers","authors":"M. Kowatari, H. Yoshitomi, Tetsuya Ohishi, M. Yoshizawa","doi":"10.15669/PNST.6.86","DOIUrl":"https://doi.org/10.15669/PNST.6.86","url":null,"abstract":"This work presents a framework of decision-making for additional monitoring of eye lens dose for radiation workers in reflect to the reduction of the annual dose limit of the eye lens dose. For a quantitative scheme to systematically estimate (non-) homogeneity of exposure, the proposed “homogeneity index (HI)” is introduced. The HIs were estimated by Monte Carlo calculations and found not to exceed up to 10 for γ-ray exposure situations. Applying the HI as a criterion of condition branching to decision-making process of additional monitoring of eye lens dose, proposed decision-making process was shown to cover entirely radiation workers required additional monitoring in the benchmark.","PeriodicalId":20706,"journal":{"name":"Progress in Nuclear Science and Technology","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73681331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to confirm accuracy of radiation transport codes, a neutron streaming experiment was conducted. An iron-polyethylene multi-layer shielding assembly was fabricated, and neutron dose distribution was measured. The shielding assembly has a three-legged rectangular duct of which the total length is 750 mm. An encapsulated Cf-252 source was set in front of the entrance of the duct to irradiate the neutron detector, and the dose along the duct was measured by the bubble detectors placed inside. The neutron dose was also calculated by the Monte Carlo codes, PHITS and MCNP5, using various nuclear data libraries, JENDL-4.0, ENDF/B-VII.1 and JEFF-3.1. The difference depending on nuclear libraries is not significant. The calculations agree well with the experiments in both cases where PHITS and MCNP5 are used.
{"title":"Experiment and analysis of neutron streaming in iron-polyethylene multi-layer shielding assembly","authors":"S. Ohnishi, Koichi Okuno, A. Konnai, K. Sawada","doi":"10.15669/PNST.6.139","DOIUrl":"https://doi.org/10.15669/PNST.6.139","url":null,"abstract":"In order to confirm accuracy of radiation transport codes, a neutron streaming experiment was conducted. An iron-polyethylene multi-layer shielding assembly was fabricated, and neutron dose distribution was measured. The shielding assembly has a three-legged rectangular duct of which the total length is 750 mm. An encapsulated Cf-252 source was set in front of the entrance of the duct to irradiate the neutron detector, and the dose along the duct was measured by the bubble detectors placed inside. The neutron dose was also calculated by the Monte Carlo codes, PHITS and MCNP5, using various nuclear data libraries, JENDL-4.0, ENDF/B-VII.1 and JEFF-3.1. The difference depending on nuclear libraries is not significant. The calculations agree well with the experiments in both cases where PHITS and MCNP5 are used.","PeriodicalId":20706,"journal":{"name":"Progress in Nuclear Science and Technology","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85192932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Tanimura, S. Nishino, H. Yoshitomi, M. Kowatari, T. Oishi
{"title":"Characteristics of commercially available CdZnTe detector as gamma-ray spectrometer under severe nuclear accident","authors":"Y. Tanimura, S. Nishino, H. Yoshitomi, M. Kowatari, T. Oishi","doi":"10.15669/PNST.6.134","DOIUrl":"https://doi.org/10.15669/PNST.6.134","url":null,"abstract":"","PeriodicalId":20706,"journal":{"name":"Progress in Nuclear Science and Technology","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86328226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nazia Neelam Shehzadi, J. Chung, In Jung Kim, B. Kim, C. Yi
The radio-photoluminescence glass dosimetry test was carried out carefully. For the test, a therapy level Co-60 gamma-ray beam was used for the irradiation of the known doses to the dosimeters with the standard uncertainty of 0.7 % (k = 1). A weak negative correlation between mass and response of the glass dosimeter was found with Pearson’s correlation coefficient -0.27, -0.29, -0.29, -0.27 and -0.26 for glass dosimeters irradiated at 1, 3, 5, 7 and 9 Gy radiation doses, respectively. It has been confirmed that the statistical uncertainty of the radio-photoluminescence glass dosimetry can be obtained within 1 % from the repeatability test.
{"title":"Preliminary study on precision dosimetry using radio-photoluminescent glass dosimeters for future use in radiotherapy","authors":"Nazia Neelam Shehzadi, J. Chung, In Jung Kim, B. Kim, C. Yi","doi":"10.15669/PNST.6.221","DOIUrl":"https://doi.org/10.15669/PNST.6.221","url":null,"abstract":"The radio-photoluminescence glass dosimetry test was carried out carefully. For the test, a therapy level Co-60 gamma-ray beam was used for the irradiation of the known doses to the dosimeters with the standard uncertainty of 0.7 % (k = 1). A weak negative correlation between mass and response of the glass dosimeter was found with Pearson’s correlation coefficient -0.27, -0.29, -0.29, -0.27 and -0.26 for glass dosimeters irradiated at 1, 3, 5, 7 and 9 Gy radiation doses, respectively. It has been confirmed that the statistical uncertainty of the radio-photoluminescence glass dosimetry can be obtained within 1 % from the repeatability test.","PeriodicalId":20706,"journal":{"name":"Progress in Nuclear Science and Technology","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91544581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shohei Iwai, F. Nobuhara, Masahiro Tanaka, Naoki Nagasawa
{"title":"Investigation of activation range for self-shielded PET cyclotron","authors":"Shohei Iwai, F. Nobuhara, Masahiro Tanaka, Naoki Nagasawa","doi":"10.15669/PNST.6.217","DOIUrl":"https://doi.org/10.15669/PNST.6.217","url":null,"abstract":"","PeriodicalId":20706,"journal":{"name":"Progress in Nuclear Science and Technology","volume":"46 3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83404864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Nishitani, K. Ogawa, Hiroki Kawase, N. Pu, T. Ozaki, M. Isobe
On the Large Helical Device (LHD), deuterium plasma experiments began in March 2017. In the plasma control, plasma heating and diagnostic systems, radiation sensitive components such as a programmable logic controller (PLC) and CCD sensors are commonly used. Three-dimensional distributions of neutron and gamma-ray in the LHD experimental building have been calculated by Monte Carlo code MCNP6 with the nuclear data library of ENDF B-VII.1 to prove the precise information on the radiation field and to introduce a countermeasure to the radiation. The total neutron flux in the torus hall of LHD is ~109 n/cm2•s for the maximum neutron yield shot. The total neutron and gamma-ray fluxes in the basement are 1-2 order smaller than those in the torus hall, which is due to the streaming through penetrations in the floor concrete slab. The shielding design for the compact neutral particle analyzer (CNPA) is also carried out. It is found that 10% borated polyethylene thicker than 15 cm is necessary for the shield in all directions.
{"title":"Monte Carlo calculation of the neutron and gamma-ray distributions inside the LHD experimental building and shielding design for diagnostics","authors":"T. Nishitani, K. Ogawa, Hiroki Kawase, N. Pu, T. Ozaki, M. Isobe","doi":"10.15669/PNST.6.48","DOIUrl":"https://doi.org/10.15669/PNST.6.48","url":null,"abstract":"On the Large Helical Device (LHD), deuterium plasma experiments began in March 2017. In the plasma control, plasma heating and diagnostic systems, radiation sensitive components such as a programmable logic controller (PLC) and CCD sensors are commonly used. Three-dimensional distributions of neutron and gamma-ray in the LHD experimental building have been calculated by Monte Carlo code MCNP6 with the nuclear data library of ENDF B-VII.1 to prove the precise information on the radiation field and to introduce a countermeasure to the radiation. The total neutron flux in the torus hall of LHD is ~109 n/cm2•s for the maximum neutron yield shot. The total neutron and gamma-ray fluxes in the basement are 1-2 order smaller than those in the torus hall, which is due to the streaming through penetrations in the floor concrete slab. The shielding design for the compact neutral particle analyzer (CNPA) is also carried out. It is found that 10% borated polyethylene thicker than 15 cm is necessary for the shield in all directions.","PeriodicalId":20706,"journal":{"name":"Progress in Nuclear Science and Technology","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80578773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Decommissioning wastes generated from decommissioning of a nuclear power plant are mainly comprised of metal wastes. These metal wastes are considered to be possible of clearance by appropriate management. Accordingly, this study is carried out to assess the possibility of clearance from the viewpoint of worker safety during the clearance of metal wastes with the aim of reducing the disposal amount of radioactive metal wastes during the decommissioning of a nuclear power plant. The assessment targets were the Boron Recovery Tank pipes and pressurizer, and the RESRAD-RECYCLE computer code was used to assess the radiological risk of each scenario. The assessment results showed that the BRT pipes met the permissible radiation dosage for clearance and the pressurizer met the permissible radiation dosage for clearance after 23 years in case of the decontamination factor of 1,000 and after 5 years in case of the decontamination factor of 10,000, respectively.
{"title":"A study on the possibility of clearance for radioactive metal wastes from decommissioning of nuclear power plants in Korea","authors":"J. Song, Dong-Min Kim, Sang Heon Lee","doi":"10.15669/PNST.6.52","DOIUrl":"https://doi.org/10.15669/PNST.6.52","url":null,"abstract":"Decommissioning wastes generated from decommissioning of a nuclear power plant are mainly comprised of metal wastes. These metal wastes are considered to be possible of clearance by appropriate management. Accordingly, this study is carried out to assess the possibility of clearance from the viewpoint of worker safety during the clearance of metal wastes with the aim of reducing the disposal amount of radioactive metal wastes during the decommissioning of a nuclear power plant. The assessment targets were the Boron Recovery Tank pipes and pressurizer, and the RESRAD-RECYCLE computer code was used to assess the radiological risk of each scenario. The assessment results showed that the BRT pipes met the permissible radiation dosage for clearance and the pressurizer met the permissible radiation dosage for clearance after 23 years in case of the decontamination factor of 1,000 and after 5 years in case of the decontamination factor of 10,000, respectively.","PeriodicalId":20706,"journal":{"name":"Progress in Nuclear Science and Technology","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79334550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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